This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study is part of a larger P01 project that is collecting follow-up data for a cohort of adults originally enrolled in the MIDUS study in 1995-96. The original study collected only interview data. The current study is designed to collect a range of biological data that will be incorporated into existing databases for the MIDUS study (an existing cohort study) in order to will elaborate the linkages between physiological functioning, health and psychosocial experience via three categories of hypotheses. The specific hypotheses within each category are illustrative of a much larger set of hypotheses of similar character.